title: 64Cu- and 68Ga-labelled [Nle(14),Lys(40)(Ahx-NODAGA)NH2]-exendin-4 for pancreatic beta cell imaging in rats.
abstract: OBJECTIVE
  Glucagon-like peptide-1 receptor (GLP-1R) is a molecular target for imaging of pancreatic beta cells. We compared the ability of [Nle(14),Lys(40)(Ahx-NODAGA-(64)Cu)NH2]-exendin-4 ([(64)Cu]NODAGA-exendin-4) and [Nle(14),Lys(40)(Ahx-NODAGA-(68)Ga)NH2]-exendin-4 ([(68)Ga]NODAGA-exendin-4) to detect native pancreatic islets in rodents.
  
  
  METHODS
  The stability, lipophilicity and affinity of the radiotracers to the GLP-1R were determined in vitro. The biodistribution of the tracers was assessed using autoradiography, ex vivo biodistribution and PET imaging. Estimates for human radiation dosimetry were calculated.
  
  
  RESULTS
  We found GLP-1R-specific labelling of pancreatic islets. However, the pancreas could not be visualised in PET images. The highest uptake of the tracers was observed in the kidneys. Effective dose estimates for [(64)Cu]NODAGA-exendin-4 and [(68)Ga]NODAGA-exendin-4 were 0.144 and 0.012 mSv/MBq, respectively.
  
  
  CONCLUSIONS
  [(64)Cu]NODAGA-exendin-4 might be more effective for labelling islets than [(68)Ga]NODAGA-exendin-4. This is probably due to the lower specific radioactivity of [(68)Ga]NODAGA-exendin-4 compared to [(64)Cu]NODAGA-exendin-4. The radiation dose in the kidneys may limit the use of [(64)Cu]NODAGA-exendin-4 as a clinical tracer.
authors.forename: Kirsi
authors.initials: K
authors.lastname: Mikkola
authors.affiliation: Turku PET Centre, University of Turku, Turku, Finland.
authors.forename: Mikkola
authors.initials: M
authors.lastname: Kirsi
authors.forename: Cheng-Bin
authors.initials: CB
authors.lastname: Yim
authors.forename: Yim
authors.initials: Y
authors.lastname: Cheng-Bin
authors.forename: Veronica
authors.initials: V
authors.lastname: Fagerholm
authors.forename: Fagerholm
authors.initials: F
authors.lastname: Veronica
authors.forename: Tamiko
authors.initials: T
authors.lastname: Ishizu
authors.forename: Ishizu
authors.initials: I
authors.lastname: Tamiko
authors.forename: Viki-Veikko
authors.initials: VV
authors.lastname: Elomaa
authors.forename: Elomaa
authors.initials: E
authors.lastname: Viki-Veikko
authors.forename: Johan
authors.initials: J
authors.lastname: Rajander
authors.forename: Rajander
authors.initials: R
authors.lastname: Johan
authors.forename: Jori
authors.initials: J
authors.lastname: Jurttila
authors.forename: Jurttila
authors.initials: J
authors.lastname: Jori
authors.forename: Tiina
authors.initials: T
authors.lastname: Saanijoki
authors.forename: Saanijoki
authors.initials: S
authors.lastname: Tiina
authors.forename: Tuula
authors.initials: T
authors.lastname: Tolvanen
authors.forename: Tolvanen
authors.initials: T
authors.lastname: Tuula
authors.forename: Marko
authors.initials: M
authors.lastname: Tirri
authors.forename: Tirri
authors.initials: T
authors.lastname: Marko
authors.forename: Eleni
authors.initials: E
authors.lastname: Gourni
authors.forename: Gourni
authors.initials: G
authors.lastname: Eleni
authors.forename: Martin
authors.initials: M
authors.lastname: Béhé
authors.forename: Béhé
authors.initials: B
authors.lastname: Martin
authors.forename: Martin
authors.initials: M
authors.lastname: Gotthardt
authors.forename: Gotthardt
authors.initials: G
authors.lastname: Martin
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Reubi
authors.forename: Reubi Jean
authors.initials: RJ
authors.lastname: Claude
authors.forename: Helmut
authors.initials: H
authors.lastname: Mäcke
authors.forename: Mäcke
authors.initials: M
authors.lastname: Helmut
authors.forename: Anne
authors.initials: A
authors.lastname: Roivainen
authors.forename: Roivainen
authors.initials: R
authors.lastname: Anne
authors.forename: Olof
authors.initials: O
authors.lastname: Solin
authors.forename: Solin
authors.initials: S
authors.lastname: Olof
authors.forename: Pirjo
authors.initials: P
authors.lastname: Nuutila
authors.forename: Nuutila
authors.initials: N
authors.lastname: Pirjo
mesh_terms: D000085:Acetates / Q000737:chemistry / Q000493:pharmacokinetics; D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography; D056831:Coordination Complexes / Q000737:chemistry / Q000493:pharmacokinetics; D003301:Copper Radioisotopes; D005710:Gallium Radioisotopes; D041981:Gastrointestinal Tract / Q000000981:diagnostic imaging / Q000473:pathology; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry / Q000493:pharmacokinetics; D006801:Humans; D050417:Insulin-Secreting Cells / Q000000981:diagnostic imaging*; D008297:Male; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000493:pharmacokinetics; D049268:Positron-Emission Tomography / Q000379:methods*; D011874:Radiometry; D051381:Rats; D017207:Rats, Sprague-Dawley; D013194:Staining and Labeling; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed
chemical_list: C000592907:(Nle14,Lys40(Ahx-NODAGA-68Ga)NH2)exendin-4; C572723:1-(1,3-carboxypropyl)-4,7-carboxymethyl-1,4,7-triazacyclononane; D000085:Acetates; D056831:Coordination Complexes; D003301:Copper Radioisotopes; D005710:Gallium Radioisotopes; D006573:Heterocyclic Compounds, 1-Ring; D010455:Peptides